You can sand blast (Cheaper than you think if you get one of those big
trucks), Soda Blast (expenisive), electric grinder/sander ( buy a
really good one), stripper (horrible), propane torch (dangerous).

I tried all - Settled on 3 step process, shovel first (it needed it),
5000 psi pressure washer second. And third hand grinder (tried 4 or 5
different attachments) Having to do this to a 70' boat, I hired an
illegal worker at 6 an hour to do last step. Also buy lots of plastic
bags, tarps and good shop vac.

If I had to it again, I would hire a sandblasting company... I think I
would have saved money.